The term ‘wireless network’ commonly refers to telecommunications networks which comprise ‘nodes’ (i.e. devices which transmit and receive information) connected by a wireless remote information transmission system that uses electromagnetic waves, most commonly radio waves, for the carrier.
Various specifications have been developed for ‘over-the-air’ interfaces between nodes, of which the 802.11 family, developed by the Institute of Electrical and Electronic Engineers (IEEE), is perhaps the best known.
Wireless networks often suffer from inefficient carrier waves usage and have a limited ability to withstand interference. Often, wireless networks use only a fraction of the assigned spectrum for data exchange. For example, in 802.11b and 802.11g, three non-overlapping channels (in 802.11a, thirteen non-overlapping channels) are available in the assigned spectrum, but only one channel is usually used for data transmissions because the channel is fixed in a given network. The channel and other transmission parameters may be fixed by an access point or may be statically configured by users. As used herein, the term ‘channel’ refers to a portion of the spectrum characterized by a central frequency and a band width. In some networks, nodes may communicate directly with one another rather than via an access point but such networks are also statically configured (i.e. the transmission channel and other transmission parameters are fixed during network setup). Multiple communicating nodes contend with each other on the same channel while other channels are under utilized.